Projectile guide for telescoped ammunition

ABSTRACT

A J-SHAPED CROSS SECTION PLASTIC GUIDE FOR TELESCOPED PROJECTILE AMMUNITION, ESPECIALLY OF THE CASELESS TYPE. A BORE OF THE AMMUNITION ROUND AND DEFINES THE FRONT END THEREOF, THE BIGHT PORTION OF THE J-SHAPED CROSS SECTION OVERLIES THE ANNULAR RING FRONT END OF THE ROUND WITH THE SHORT LEG OF THE J DEFINING A PORTION OF THE OUTER DIAMETER OF THE ROUND. THE CYLINDRICAL PORTION OF THE GUIDE IS DESIGNED TO BE STRIPPED FROM THE REMAINDER THEREOF BY   THE PROJECTILE DURING FIRING AND CARRIED OUT OF THE WEAPON THROUGH THE BARREL THEREOF. THE REMAINDER OF THE GUIDE IS EITHER CONSUMED DURING FIRING OR BROKEN UP AND FORCED THROUGH THE BARREL BY THE PROJECTILE GASES.

United States Patent Ofice US. Cl. 102--38 7 Claims ABSTRACT OF THE DISCLOSURE A J-shaped cross section plastic guide for telescoped projectile ammunition, especially of the caseless type. A cylindrical portion of the guide extends into the central bore of the ammunition round and defines the front end thereof; the bight portion of the J-shaped cross section overlies the annular ring front end of the round with the short leg of the J defining a portion of the outer diameter of the round. The cylindrical portion of the guide is designed to be stripped from the remainder thereof by the projectile during firing and carried out of the weapon through the barrel thereof. The remainder of the guide is either consumed during firing or broken up and forced through the barrel by the projectile gases.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to ammunition and more particularly to a front end guide for a telescoped projectile used in connection with caseless ammunition.

Prior art Recently, ammunition rounds of the type known as a cartridge with a telescoped projectile have been developed. A usual embodiment for such cartridges is found in caseless ammunition, where the entirety of the round is constructed of the projectile and propellant without the use of a casing. Such cartridges consist basically of molded propellant which has a central bore extending thereinto from the front end thereof; the projectile being telescopically received in the bore.

While such a design eliminates the difficulties otherwise inherent in attaching the projectile to a caseless cartridge, the design itself has certain disadvantages. When the cartridge is inserted in the firing chamber of a weapon, the front end, which is constructed of molded propellant, may contact the hot end of the weapon barrel, causing a cook-off or even a premature ignition. Additionally, the tubular front end is subject to damage during rough handling and it is possible for the projectile to fall out of the bore during such handling. The greatest disadvantages of such a design lie in the lack of front end obturation and the possibility of misalignment between the exiting projectile and the weapon barrel. When the propellant is fired, it is possible for the gases to encircle the projectile and provide a flow of gas in front of the projectile and out the barrel. This can occur inasmuch as until the largest diameter portion of the projectile enters the weapon barrel and begins to be engraved by the rifling of the barrel, there is no sealing of the gases behind the projectile. It is of course obvious that if a significant portion of the propellant gases is allowed to escape past the projectile, the operating characteristics of the ammunition are greatly lessened.

Additionally, as the projectile begins to telescopically exit from the cartridge, because the interior diameter wall of the cartridge is formed solely of molded propellant, it is possible for the projectile to become canted therein 3,616,752 Patented Nov. 2, 1971 or simply misaligned with the receiving end of the barrel. When this occurs, the projectile can become damaged as it enters the barrel and repeated misalignment can damage the weapon.

SUMMARY The present invention overcomes the above disadvantages of telescoped ammunition and provides for a projectile guide and front end obturator for use with such ammunition.

The projectile guide comprises a main tubular portion with an outturned flange at one end thereof and a secondary shorter tubular portion depending from the outer diameter of the flange providing, in cross section, a J- shaped guide. The guide is adapted to be slipped into the end of the ammunition cartridge with the outturned flange overlying the tubular ring end of the cartridge and the short leg of the 1 providing the outer diameter of the cartridge at the end thereof. The main tubular portion of the guide is designed to have an outer diameter equal to the bore of the cartridge and an inner diameter which provides an interference fit between the main body portion of the projectile and the guide. This will retain the projectile in the cartridge during handling while at the same time providing for front end obturation during firing. The obturation is provided because the interference fit prevents the gases from escaping around the circum ference of the projectile into the barrel of the weapon.

The guide is designed to be preferably used with a projectile which has an increased-diameter ring portion adjacent its trailing end. As the projectile is forced telescopically out of the cartridge during firing of the round, the increased diameter ring portion will strip the main tubular portion of the guide away from the flange portion and carry it into the weapon barrel along with the projectile. As the guide enters the barrel, if it has an outer diameter approximately equal to the outer diameter of the increased diameter ring portion, it can aid the ring portion in imparting a spin to the projectile due to the rifling of the barrel. After exiting of the projectile, the remaining portion of the guide will be broken up by the propellant gases and carried out of the weapon through the barrel.

The projectile guide is preferably made of a material such as a plastic or the like, which has greater strength than the molded propellant of the round. It is of course to be understood that the projectile can be made of other material including but not limited to metals, papers, etc. Although the projectile guide will be described in a preferred embodiment in connection with a molded propellant caseless ammunition round, it is to be understood that the principles of this invention may be practised with any form of telescoped ammunition.

It is therefore an object of this invention to provide a new type of ammunition cartridge.

It is a further object of this invention to provide an improved front end obturator and projectile guide for telescoped ammunition cartridges.

It is yet another and more important object of this invention to provide a front end obturator and projectile guide for use in connection with telescoped ammunition which includes an elongated tubular portion with a flared outwardly directed flange at one thereof which is adapted to be inserted into the open bore of a telescoped projectile cartridge with the flared flange overlying and defining the end of the cartridge.

It is yet another and more important object of this invention to provide a front end obturator and projectile guide for telescoped ammunition having a portion designed to be stripped from the cartridge by the exiting projectile and carried out of the weapon through the barrel thereof.

It is yet another object of this invention to provide a front end obturator and projectile guide for telescoped ammunition which is adapted to retain the projectile within the cartridge, provide front end sealing to prevent gases from the burning cartridge from flowing in front of the projectile, prevent front end cook-off of the cartridge from contact between the cartridge and a hot barrel end, guide the projectile into the barrel and be totally consumed or ejected from the weapon during firing of the cartridge.

Other and further objects of this invention will be apparent to those skilled in this art from the following detailed description of the annexed sheets of drawings which, by way of a preferred embodiment of the invention, illustrate one example of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of the projectile guide of this invention.

FIG. 2 is an end plan view of the projectile guide of this invention.

FIG. 3 is a cross-sectional view of the caseless ammunition round having a telescoped projectile therein and equipped with the projectile guide of this invention.

FIG. 4 is a cross-sectional view of a weapon firing chamber and barrel end during the firing of the cartridge of FIG. 3.

FIG. 5 is a view similar to FIG. 4, taken sequentially shortly after the view of FIG. 4, and illustrating the stripping of the center portion of the projectile guide of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates in cross section the projectile guide of this invention, where the guide includes an inner tubular portion 11 having an outturned flange 12 at one end thereof which is integral with a second coaxial shorter outer tu bular portion 13 at the outer diameter of the flange 12. Therefore, in cross section the projectile guide 10 is J-shaped. As can be seen in FIG. 2, the end view of the projectile 10 is that of a ring having a central bore 14. The projectile guide is preferably made of some material such as plastic, polyacetal, etc. It is to be understood, however, that the guide can be made from any material having a sufficient strength to perform the functions required of the guide and yet a sufficient shear Weakness to allow it to be broken up during firing of the cartridge. Alternatively, the guide could be made of a material having the desired strength characteristics but which is designed to be consumed by the heat generated during firing of the cartridge.

FIG. 3 illustrates the guide 10 installed in a telescoped projectile caseless ammunition cartridge 15. The cartridge includes a projectile 16 which is telescopically received in a bore 17 of a molded propellant body 18. The molded propellant body 18 includes a primer portion 19 and may include a gas cavity 20 which may either be vacated or filled with a propellant of a differing consistency. The projectile includes a tapered front end 21, a constant diameter main body portion 22, and an increased diameter ring portion 23 which is adjacent the trailing edge 24 of the projectile. The projectile is positioned within the bore 17 and is enveloped by the body 18 of the cartridge 15.

The diameter of the bore 17 is preferably approximately the same as the diameter of the increased diameter ring portion 23 and an interference fit may exist between the interior diameter of the bore and the ring 23. The cartridge is constructed entirely of molded propellant which is designed to be totally consumed during firing of the cartridge. Because of this, the cartridge body is not as strong as a standard metal cased cartridge, and problems would be encountered in attempting to attach the projectile to the front end of the cartridge. For this reason, the idea of embedding the projectile in the cartride has many desired advantages. However, because of the weakness of the molded propellant, many of the above-rnentioned disadvantages are encountered.

In many cases, the weakest portion of the molded body 18 is that portion 25 which defines the front end of the cartridge radially outwardly from the tapered end 21 of the projectile. In such a design, there is no radial support for the front end and it can become chipped and damaged during rough handling. In addition, because the projectile is held in the bore 17, only by an interference fit between it and the inner diameter, it is possible for the projectile to become dislodged during rough handling. Additionally, when the cartridge is inserted into a rapid-fire weapon, the ring-like front end 26 may be forced into contact with the hot end of the weapon barrel, thereby causing a coo'k-ofl or premature ignition of the front end of the molded propellant body. Additionally, when the cartridge is fired, it is possible for the gases generated during burning of the propellant to pass around and in front of the projectile and exit out the barrel of the weapon without giving their impetus to the movement of the projectile. Prior to the time the increased diameter ring portion 23 enters the weapon barrel and becomes enmeshed in the rifiing thereof, a seal is not formed which would prevent the above-described gas flow in front of the projectile. Additionally, it is possible that due to the weakness of the molded propellant and damages or dislocations caused by rough handling, that the projectile 16 may not be properly aligned with the end of the weapon barrel. One cause of such misalignment can be the lack of a set outer diameter at the front end of the cartridge due to chipping or erosion of the molded propellant. In such cases, firing of the cartridge may cause the projectile to be damaged while entering the barrel. Repetitive firing of such misaligned shells can cause further damage to the barrel end. These disadvantages are all overcome by the present invention.

The projectile guide 10 is designed to be fitted onto the front end 25 of the cartridge with the first tubular portion 11 inserted into the bore 17 of the cartridge. The interior diameter measurement of the projectile guide 10 and the axial length thereof are chosen to provide an interference fit between the inner diameter of the projectile guide and the main body portion 22 of the projectile 16. This interference fit aids in retaining the projectile within the casing during handling thereof. The outturned flange portion 12 is dimensioned to overlie the front end 26 of the cartridge and thereby define the front end of the cartridge. It can therefore be seen that the first tubular portion 11 provides a radial support for the front end of the cartridge while the flange 12 provides axial support and prevents the above-mentioned premature firing or cook-off. The second tubular portion 13 defining the short leg of the J cross section is dimensioned to be coplanar with the outer diameter 27 of the cartridge body 1 8 and provide part of the outer diameter of the cartridge at the front end thereof. The provision of the short leg portion 13 aids in attaching the projectile guide 10 to the cartridge body 18 and creates a definite set outer diameter in order to align the cartridge in the firing chamber of the weapon. However, it is to be understood that many of the advantages of this invention can be derived from an L-shaped cross section projectile guide as well as from the J-shaped cross section guide. That is to say that many of the advantages of this invention can be provided with a projectile guide containing only the tubular portion 11 and the flange portion 12.

Because of the interference fit between the projectile 16 in its main body area 22 and the inner diameter of the guide 10, a front end obturator is provided. Gases attempting to flow past the projectile 16 will be entrapped by the sealing interference fit between the inner diameter of the portion 11 of the guide and the projectile. Gases attempting to flow between the portion 11 and the molded propellant or firing chamber will be entrapped by the flange 12 and theportion 13. Additionally, the projectile guide serves to properly align the projectile with the bore of the weapon barrel inasmuch as it has a constant outer and inner diameter. As the projectile is fired out of the telescoped shell, the projectile guide 10 will guide the projectile properly into the barrel.

FIG. 4 illustrates the cartridge of FIG. 3 in place in the firing chamber 30 of a weapon 31 and in properly aligned position with the bore 32 of the barrel 33. The figure illustrates the position of the projectile during the early stages of firing of the cartridge when it has been telescopically moved forward until the front end 21 is in the weapon barrel 32 and the increased diameter ring portion 23 has contacted the inner tubular portion 11 of the guide 10. It can be seen that in this position the guide 10 is still acting as a front end obturator preventing the gases being generated by the burning of the molded propellant from escaping around the projectile into the barrel 32. a

As can be seen frornFIG. 4, the guide 10 provides total front end obturation of the propellant gases. Those gases attempting to flow around the projectile will be stopped due to the interference fit between the main body portion 22 of the tubular portion 11 of the guide. Those gases attempting to flow between the projectile guide and the interior diameter wall of the firing chamber 30 will either be stopped because of the interference fit of the outer diameter of the tubular portion 11 and the inner diameter of the molded body portion 18 of the bore 17 of the cartridge or will encounter the flange portion 12. Gases building up at the front end of the projectile guide will expand the second tubular portion v13 into tight sealing contact with the inner diameter of the firing chamber, press the flange portion 12 against the barrel end and expand the tubular portion 11 to increase the sealing between the inner diameter of that portion and the projectile.

As is illustrated in FIG. 5, as the projectile 16 passes through the guide 10, the tubular portion 11 is stripped from the flange portion 12 by contact with the increased diameter ring portion 23 which results in shearing off of the tubular portion 11 and carrying it into the weapon barrel 32 along with the remainder of the projectile. At this point, the rifling 35 of the barrel 32 will begin to engrave the ring portion to impart a spin to the projectile 16. In those cases where the outer diameter of the tubular portion 11 is the same as the bore of the barrel 32, the projectile 11 will also encounter the rifling 35 and be rotated along with the projectile.

After the projectile has entered the weapon barrel, the continuous burning of the molded propellant and the turbulence of the propellant gases released thereby will cause the outturned flange portion 12 and the second tubular portion 13 of the projectile guide 10 to break up and be thrust out of the firing chamber 30 into and through the bore 32 of the weapon barrel. In this manner, it can be seen that the entirety of the projectile guide 10 is expelled from the weapon during firing, the tubular portion 11 having been carried out by the projectile and the flange portion 12 and second tubular portion 13 being thrust out by the action of the propellant gases. In this manner, the projectile guide 10 does not detract from the basic idea of a caseless cartridge; nothing remains in the firing chamber at the end of the firing sequence.

Although the flange and second tubular portions have been described as being broken up by the propellant gases and forced out of the barrel, it is to be understood that they could be constructed of a material which will be entirely combusted or consumed during the firing cycle, the important point being that nothing remains within the firing chamber after completion of the firing cycle.

Although the invention has been described as used in connection with a caseless ammunition round, it is obvious that the advantages of this invention, especially the guiding and obturation features, can be advantageously utilized in connection with all forms of ammunition with telescoped projectiles.

Although we have herein set forth our invention w1th respect to certain specific principles and details thereof, it will be understood that these may be varied without departing from the spirit and scope of the invention as set forth in the hereunto appended claims.

We claim as our invention:

1. A device for use in connection with telescoped projectile ammunition cartridges dimensioned for use 1n a gun having a barrel bore with a given ma or diameter which comprises: a first tubular portion adapted to be inserted into the central bore of the cartridge, said first tubular portion having an outer diameter not greater than the major diameter of the barrel bore, an outturned flange portion integral with one end of the first tubular portion adapted to overlie the front end portion of the cartridge, and a second tubular portion integral with the radially outermost periphery of the flange portion adapted to define part of the outer diameter of the said cartridge, the said device having a J-shaped cross section.

2. A projectile guide for use with telescoped pro ectile ammunition dimensioned for use in a gun having a barrel bore with a given major diameter comprising: a first tubular portion adapted to be received within apro ectile containing bore in the cartridge, the inner diameter of said guide adapted to engage the body of the sa1d projectile to provide front end obturation during firing, the outer diameter of said first tubular portion of sa1d gulde having a dimension not greater than the major diameter of the barrel bore, an outturned flange portion integral with the said tubular portion adapted to define the front end of the said cartridge, and an outer diameter portion integral with the flange portion adapted to give the said guide a defined outer diameter to fit within the firing chamber of a weapon aligning the projectile with the barrel of the weapon.

3. In a caseless ammunition cartridge having a telescoped projectile received within a bore extending into the cartridge from the front end thereof, the 1mprovement of a projectile guide associated with said cartridge, said guide including means for aligning the said projectile with the bore of a weapon when the said cartridge is inserted in the firing chamber of the weapon, means for front end obturation of the propellant gases developed by the firing of the said cartridge whereby the said gases are retained behind the said projectile, sa1d guide having a frangible connection between a first portion and a second portion thereof, the inner diameter of the said first portion being substantially constant, the said projectile having an increased diameter portion therearound positioned behind the said first portion, and dimensioned to contact the rear of the said first portion to sever it from the said second portion upon firing of the projectile, and the said guide adapted to be broken up and thrust out of the weapon during completion of the firing cycle.

4. An ammunition cartridge comprising: a molded propellant body portion having a cylindrical front end, a bore extending into said front end, a projectile telescopically received within said bore, a projectile guide extending into said bore from the front thereof, said projectile guide having an outturned flange associated therewith overlying the front end of said body and an expansible sealing tubular portion integral with said flange around the outer periphery thereof adapted to expand into sealing engagement with the inner diameter of the firing chamber of a weapon during firing of the cartridge.

5. The cartridge of claim 4 wherein the said projectile has an increased diameter portion adjacent the rear thereof and the portion of the said projectile guide lying within the said bore is adapted to be sheared from the said flange portion under the force of contact between it and the increased diameter portion of the projectile, whereby the said sheared portion is carried out of the barrel of a weapon firing the cartridge along with the said projectile.

6. The cartridge of claim 5 wherein the flange portion and the outer diameter tubular portion of the said guide are adapted to be broken up by the projectile gases and expelled from the weapon through the barrel thereof during the firing cycle.

7. A front end obturator for a telescoped projectile cartridge which has the projectile received in an axial bore opening to the front of the cartridge which comprises: a first tubular portion extending into the bore adapted to circumferentially encircle a portion of the projectile, a flange portion at the front end of said first tubular portion adapted to overlie the front end of the cartridge radially out from the bore, a second tubular portion integral with the flange portion adjacent the outer periphery thereof adapted to define the outer diameter of a portion of the cartridge, the said first tubular portion adapted to be expanded radially inwardly into sealing interface circumferential engagement with the projectile by the action of propellant gases acting on said first tubular portion, the said second tubular portion adapted to be expanded radially outwardly into sealing circumferential interface engagement with the inner diameter of a weapon firing chamber under influence of the propellant gases whereby the front end of the firing chamber is sealed by the o'bturator to prevent gases from the burn-. ing propellant from escaping in front of the projectile, a frangible connection between the said first tubular portion and the said flange portion, an increased diameter portion on the said projectile, said increased diameter portion positioned behind the said first tubular portion, the outer diameter of the said increased diameter portion being greater than the inner diameter of the said first tubular portion whereby the said increased diameter portion of the projectile will contact the said first tubular portion during firing to shear it from the said flange portion at the frangible connection therebetween.

References Cited UNITED STATES PATENTS 1,353,118 9/1920 Thompson 102-38 1,470,591 10/1923 Behar 10238 2,866,412 12/1958 Meyer et al. l0238 3,114,290 12/ 1963 Harvey et al. -89-26 ROBERT F. STAHL, Primary Examiner US. Cl. X.R.

10293; Digest 1 

